/*
 * The code in this file is taken from a blog post by Phillip Sumi,
 * 'Finding an ancestor of a WPF dependency object', at his blog
 * at http://www.hardcodet.net/. (The post in question can be found
 * at http://www.hardcodet.net/2008/02/find-wpf-parent).
 */

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;

namespace Sussex.Flip.Utils
{
	/// <summary>
	/// Description of UIHelper.
	/// </summary>
	public static class UIHelper
	{
		/// <summary>
		/// Finds a parent of a given item on the visual tree.
		/// </summary>
		/// <typeparam name="T">The type of the queried item.</typeparam>
		/// <param name="child">A direct or indirect child of the
		/// queried item.</param>
		/// <returns>The first parent item that matches the submitted
		/// type parameter. If not matching item can be found, a null
		/// reference is being returned.</returns>	
		public static T TryFindParent<T>(this DependencyObject child) where T : DependencyObject
		{
			//get parent item
			DependencyObject parentObject = GetParentObject(child);
		
			//we've reached the end of the tree
			if (parentObject == null) return null;
		
			//check if the parent matches the type we're looking for
			T parent = parentObject as T;
			if (parent != null) return parent;
			else {
				//use recursion to proceed with next level
				return TryFindParent<T>(parentObject);
		  	}
		}
	
		
		/// <summary>
		/// This method is an alternative to WPF's
		/// <see cref="VisualTreeHelper.GetParent"/> method, which also
		/// supports content elements. Keep in mind that for content element,
		/// this method falls back to the logical tree of the element!
		/// </summary>
		/// <param name="child">The item to be processed.</param>
		/// <returns>The submitted item's parent, if available. Otherwise
		/// null.</returns>
		public static DependencyObject GetParentObject(this DependencyObject child)
		{
			if (child == null) return null;
	
			//handle content elements separately
			ContentElement contentElement = child as ContentElement;
			if (contentElement != null)
			{
			DependencyObject parent = ContentOperations.GetParent(contentElement);
			if (parent != null) return parent;
	
			FrameworkContentElement fce = contentElement as FrameworkContentElement;
			return fce != null ? fce.Parent : null;
			}
	
			//also try searching for parent in framework elements (such as DockPanel, etc)
			FrameworkElement frameworkElement = child as FrameworkElement;
			if (frameworkElement != null)
			{
			DependencyObject parent = frameworkElement.Parent;
			if (parent != null) return parent;
			}
	
			//if it's not a ContentElement/FrameworkElement, rely on VisualTreeHelper
			return VisualTreeHelper.GetParent(child);
		}
		
		
		public static string Truncate(string str, uint length)
		{
			if (String.IsNullOrEmpty(str)) return String.Empty;
			
			if (str.Length <= length) return str;
                                
			return String.Format("{0}...",str.Substring(0,(int)length-1));
		}
	}
}
